Apparatus for cooling or freezing



May 22, 3934,

M. H. AcKr-:RMAN

APPARATUS FOR COOLING OR FREEZING Filed May 30, 1933 www5 5 Sheets-Sheet l INVENTOR www BY new ATTORNEY May r22, 1934.

M. H. ACKERMAN APPARATUS FOR COOLING OR FREEZING Filed May 30, 1955 lilly* 3 Sheets-Sheet 5 INVENTOR ATTORNEY Patented May 22, 1934 1,960,075 APPARATUS FOR COOLING OR FREEZING Michael H. Ackerman, Mansfield, Ohio, assignor to The H. H.

Miller Industries Company,

Canton, Ohio, a corporation of Ohio Application May 30, 1933, Serial No. 673,719

17 Claims. (Cl. 62-114) This invention relates to apparatus for applying a volatile liquid refrigerant to the walls of an evaporator adapted to receive and hold liquids or semi-liquids from which heat is to be extracted in such' manner that thermal syphon refrigerant circulation means are entirely eliminated, insulating conditions due togtheformation of gas pockets on the evaporator walls are prevented, rapid separation of the generated gases from the liquid refrigerant is effected and unobstructed upward iiow of the separated gases is provided for. In the use of the term evaporator I comprehend receptacles forming parts of various apparatus, such as pasteurizers, holders, coolers and freezing mechanisms, one of the latter mechanisms being chosen as showing the preferred application of my invention. i

The illustrated construction embodying my present invention effects freezing of mixes in an evaporator by the direct application to its walls of a volatile liquid refrigerant, which is circu-` lated by mechanical means in a manner to cause the refrigerant to flow at a relatively rapid rate over and in continuous intimate contact with the evaporator walls, as long as heat transfer is required.

One object of the present invention is to simplify the construction shown in my co-pending application Ser. No. 565,425, filed September 28,

Another object of the invention is to provide an insulated casing having incorporated therein an evaporator in spaced relation to the` walls of the casing so as to effect automatically separa- 35 tion of the liquid'refrigerant from the gases generatd by the transfer of heat through the walls of the evaporator.

Another object of the tile liquid refrigerant and incorporating there- Within an evaporator and means for applying to or cutting off the supply of the refrigerant from the walls of the evaporator, whereby thermal syphonic circulation or flooding of the refrigerant 1'nto and out of the enclosing casing is eliminated. Another object of the invention is to provide an improved freezing or cooling mechanism using a volatile liquid refrigerant and comprising a casl ing serving as an enclosure for an evaporator, an riccumulator for the refrigerant and a gas separator and asa means in connection with a liquid distributing device above the evaporator for applying the liquid refrigerant to the latter, the

evaporator being enclosed within the casing in spaced relation to its walls but above the level invention is to provide an improved evaporator enclosing casing for a vola-l of the refrigerant therein, whereby the refrigerant freely flows over the evaporator walls and automatically scours therefrom resulting gas pockets or bubbles and insures separation of the latter from the liquid. This arrangement and operation or process provides for the rapid transfer of heat units through the evaporator walls.

vAnother object of the invention is to provide an improved freezing or cooling mechanism using a volatile liquid refrigerant and comprising a closed casing for the refrigerant and an evaporator within the casing in such relation to the supply of refrigerant therein that the refrigerant may be readily utilized to effect or cut off the heat transfer, whereby successive batches of material may be rapidly treated without delay between them.

Another object of the invention is .to provide an improved freezing or cooling mechanism using volatile liquid as a refrigerant and comprising a closed casing connected to a suction pipe and forming an accumulator for a substantially predetermined supply of the liquid and a gas separator, means for elevating the liquid within the casing to the space above its normal level and a material holding evaporator disposed in the path of the gravitating liquid but above its normal level, whereby the walls of the evaporator are Washed by the liquid tomaintain them free of gas pockets or bubbles.

Another object of the invention is to provide an improved freezing or cooling mechanism for liquid material using a volatile liquid as a re frigerant and comprising a closed casing for the liquid and a material holding evaporator therein vand means for readily applyingl or cutting off refrigeration to the Walls of the evaporator without removal ofthe liquid from the casing.

Another object of the invention is to provide an'improved material freezing or cooling mechanism using a volatile liquid as a refrigerant in which the liquid holding vcasing and material' holding evaporator and liquid circulating means are combined in a unitary structure', whereby its walls may be effectively insulated to eliminate exposed parts that would. ,otherwise become frosted and wasted refrigeration.`

Another object of the invention is to incorporate with the evaporator casing improved means for separating from the liquid refrigerant any lubricant which may collect in the refrigerant..

Other objects of the invention will be apparent to those skilled in the art to which my invention relates from the following description taken in connection with the accompanyin drawings, wherein Fig. 1 is a view of a. freezing or cooling mechanism embodying my invention, partly in elevation and partly in section on the line 1-1 of Fig. 2.

- Fig. 2 is a section on the line 2--2 of Fig. l.

Fig. 2a. is a section on the line Zat-2a of Fig. 1. Fig. 3 is a fragmentary section substantially on the line 3-3 of Fig. l, enlarged.

Figr 4 is a fragmentary section on the line Ll--Ji f Fig. 1, enlarged.

Fig. 5 is a view similar to Fig. 1 but embodying a different form of liquid refrigerant elevating and distributing means.

Fig. 6 is a section on the line 6-6 of Fig. 5.

Referring to Figs. 1, 2, 3 and 4 of the drawings, 1 indicates a support comprising a hollow casting preferably having a, flaring base 1a, a rear portion'forming a bed 1b and a forwardly extending case 1c. The purpose of 'the bed 1b and 1c will later appear.

2 indicates as an entirety an evaporator which, in the present disclosure, is adapted to contain material from which heat is to be extracted, for example, in making ice cream, ices and similar products; such container and the agitating mechanism therein being preferably applicable for freezing such products in successive batches. The evaporator 2 comprises a cylinder 2a having a rear head 2b and a front head2c. The cylinder 2a may be centrifugally cast from suitable metal or formed from a plate of suitable material rolled into cylindrical form. The walls of the cylinder are of a thickness to resist external pressure. The inner end of the cylinder 2a is secured liquid-tight in any desired manner to the rear head 2b. 'Ihe rear head is suitably secured to the bed 1b. rl'he front head 2c is removably secured in a liquid tight manner to an annular seat provided on a substantially annular member 2d. The member 2d consists of a ring 2e carrying the annular seat and surrounded by a plate 2f, the lower portion of which is suitably secured to the front wall 1c of the case 1c, such connection and the connection of the rear head 2b to the bed 1b serving to mount the evaporator 2 on the support 1 and also otherl parts hereinafter referred to. The rear head 2b is provided with an inlet duct 3 connected with a valve controlled supply pipe 4 leading from a suitable measuring tank 4d. The front head 2c is provided with a valve controlled outlet 5. The head 2c may be constructed and removably mounted as shown in Letters Patent No. 1,449,623, granted to Leroy S. Pfouts. 6 indicates an agitating and ejecting mechanism within the cylinder 2a. and preferably comprising inner and outer rotatable members, the outer member comprising spiders carrying suitable Scrapers 7 and one or more ejecting elements 7a and the inner member comprising a shaft 9 carrying propelling blades 7b. The f spiders rotate on the shaft 9, the inner spider being connected to a shaft 10. \The agitating and ejecting mechanism is preferably constructed similar to that shown in Letters Patent No. 1,692,964. The outer end of the shaft 9 is suitably mounted in the front head 2c. The two shafts 9, 10, extend through the rear `head 2b and are driven in a well known manner by a suitable driving mechanism 8. "The driving mechanism 8 is suitably mounted on the bed 1b and consists of an electric motor 8 the shaft of which operates through suitable reduction gearing, within the casing 8x, to drive gears within the gear box 8x'. the shafts 9, 10, which in turn are connected to the inner end and outer rotatable members of the mechanism 6 to rotate them in opposite directions.

11 indicates as an entirety an evaporator enclosing casing the purpose of which is to serve asv -an accumulator for a predetermined supply of a volatile liquid refrigerant, such as liquid ammonia, and a gas separator. 12 indicatesas an entirety means for elevating the refrigerant above the evaporator and distributing itl thereon, whereby its cycle of circulation and application are controlled. In the present application of my invention, the casing 11 surrounds the side walls or body of the evaporator in spaced relation thereto, leaving the rear and front heads 2b, 2c, exposed, so that the supply of the mix or material to the evaporator and its discharge therefrom, application of mechanical power to the agi-J tating mechanism 6 and removal and replacement of the agitating mechanism, are provided for in a simplified manner, independently of the easing 11, and storing and circulation of the refrigerant. The casing 11 comprises a body 11a and rear and front end plates 11b, 11o, which are formed with openings through which extend the end portions of the cylinder 2a. The walls of the openings in the plates 11b, 11c, are secured (as by welding) to the cylinder 2a in a liquid and gas tight manner.

The upper portion of the body 11a is of semicylindrical shape and its side portions extend downwardly, preferably in converging relation, so that the lower portion of the casing may conveniently t within the case 1c. The uppermost portion of the casing 11 is provided with a gas outlet 11', connected with a pipe 13, which leads to the suction side of a compressor (not shown) The pipe 13 may be provided witha back pressure valve (not shown). As shown in Fig. 2, the walls of the casing body are disposed in spaced relation to the Walls 2a of the evaporator 2 and the upper cylindrical portion of the bodyl in the preferred arrangement is disposed eccentrically to the adjacent portion of the evaporator wall. In this arrangement the flow space for the liquid is progressively larger towardthe upper portion of the ow space to compensate for the increased The gears are connected to volume of gas, which is generated by reason of the transfer of heat as the refrigerant ows over the Walls of the evaporator (especially Where the temperature of the mix is relatively high), and to insure discharge of the gas to the pipe 13 in a dry condition. i

. 1 The body walls 11a (top, sides and bottom) and end Vplates 1lb, llc of the casing are covered with suitable insulation 14 and the exposed portions of the latter are covered with a sheathing 15. 'Ihe inner wall of the casing 1c is in- 135 sulated, as shown at 14a, as a supplemental protection against heat transfer tovprevent boilply of liquid ammonia and connected to the casving 11, to supply ammonia thereto to replace that which gasies or is used up to effect cooling or freezing. The pipe 16 is provided with a magnetically operated valve 1'7, the coil of which is energized and deenergized by a switch 18, the

latter in turn being operated to close and open the circuit for the coil by a float mechanism, indicated as an entirety at 19. The pipe 16 may lead into the casing 11 at any desirable point, for example, above the oil separating means, indicated as an entirety at 11x, as shown in Figs. 1 and 2, or below such means as shown in Figs. 5 and 6. Of the oat mechanism 19, 20 indicates a hollow member closed at its outer end by a head 21 and removably mounted in an opening formed in the end plate 11b, the marginal portions of the head being secured to the plate 11b by bolts. The inner end of the member 20 is provided with diametrically arranged lugs 22 having aligned threaded openings for threaded pins 23, which serve as trunnions for a rocker 24. The rocker consists of a sealed tube 25, in which the switch 18 is mounted, and a float 24a flxedly connected to the rocker by a rod 24.

The outer end of the tube 25 is internally threaded to receive a plug 26 which is sealed by a gasket 27. 'Ihe switch 18 is preferably of the mercoid type and the leads therefrom are carried through openings formed in the inner end wall of the tube 25 and pipes 28 to a point exterior of the casing 11, so that the leads and switch are protected or sealed from the liquid refrigerant. The inner ends of the pipes 28 are sealed in their openings by a gland compressed by threaded, hollow members 29 which, when tightened, connect the pipes to the end wall of the tube 25. The outer end portions of the tubes 28 extend through and are suitably sealed in openings formed in the head 21 in a similar manner by theaded, hollow, members 30. The weight of the float 24a is partially off-set or counterbalanced to the desired extent by weights 31, so that it will readily respond to the rise and fall of the refrigerant level. 'The tubes 28 are formed of slightly resilient material and are coiled in opposite directions so as to act in opposition to each other without affecting the normal operation of the float but tending to prevent undue movement thereof in either direction.

In the form of construction shown in Figs. 1

and 2, the refrigerant circulating and distributf ing means 12'comprises a pump 32, a distributing device 33 in the evaporator casing 11 above the cylinder 2a and a liquid connection or pipe 34 between the outlet from the pump and said distributing device.

The distributing device 33 comprises a hollow member disposed centrally above the container 2 and extending substantially from end to end thereof and formed on its lower side with ports or openings to direct or distribute the liquid refrigerant in spray form or in small streams uniformly onto the evaporator wall. Obviously, the wall of the device may be provided with one or more rows of openings; also, in place of openings, nozzles or nipples may be used. The front end of the distributing device 33 is closed by a removable plug 35 (threaded into the end of the device), which is provided with tool engaging means. The plate 2f is provided with an opening 2f' to permit access to the plug 35, such opening being closed by a suitable shutter. The rear end of the distributing device 33 is connected by an elbow 33 to the upper end of the supply pipe 34. The lower end of the pipe 34 is connected to the discharge duct of the pumping mechanism 32 by an elbow 33a. The pumping mechanism 32 is preferably of the centrifugal type. Of this pumping mechanism, 36 indicates a suitable casting having a main portion shaped to form a recess to accommodate the rotating member37 and .a tubular portion 38. The main portion of the casting 36 is provided with a ange 39, which is removably bolted to the end plate 11b, so that such portion and the plate form a casing for the rotating member 37. The recess for the rotating member 37 is shaped to provide a flow space or channel 39' for the liquid refrigerant, which space or channel terminates in a discharge conduit 40. The outer end of the conduit 40 registers with an opening formed in the end plate 11b, which opening, by means of the elbow 33a is connected to the lower end of the pipe 34. The intake for the rotating member 37 is provided axially thereof by an opening in the wall of the plate 11b, which opening registers with one end of a pipe 42'; the other end of the pipe 42 leading through the bottom wall` of the casing 11 and terminating at a point slightly above such wall for a purpose later to be set forth. The pipe 42 is adapted to convey the liquid refrigerant from the casing 11 to the rotating member 37, which forces it through the conduit 40, elbow 33a and pipe 34 to the distributing device 33. The main portion of the casting 36 is preferably formed within the flange 39 with an annular recess 43 to receive an annulus 44, which closes the channel 39'. The rotating member comprises a disk 37 A having on its inner face uniformly spaced vanes 45 and a circular plate 46 bridging the spaces between the vanes. Each vane 45 has inwardly converging side walls so arranged that (l) each side wall of each vane is parallel to and spaced from but relatively close to the opposed side wall of the next or adjoining Vanes and (2) each space extends at an angle of approximately 111/2 degrees to a radius of the member which radius medially cuts the outer end of the space, the inner end of the space being forward of such radius with respect to the direction of rotation of the member 37. The disk 37' is secured to the reduced inner end of a shaft 47 by a nut 48. Theshaft 47 extends through the tubular portion 38, being supported therein by suitable spaced anti-fric-v tion bearings; and the outer end of the shaft 47 is connected through a exible coupling 49 to the shaft of an electric motor 50, mounted on a sub-base 1d. A sealing means 51' is provided inwardly of the inner shaft bearing between the shaft 47 and the opening in the wall of the main portion of the casting 36, to prevent leakage of the liquid ammonia along the shaft. The tubular portion 38 forms a reservoir for a lubricant for theshaft bearings.

Of the oil separating means 111:, 51 indicates a plate extending across the bottom of the casing 11 in spaced relation thereto, being supported in such position by suitable blocks. The plate 51 engages the front and rear walls 11b, llc, of the casing 11 and the longitudinal side edges of the plate engage the side walls 11 of the latter, but these edges are roughened, serrated or notched to form openings 51a to permit any oil, which may collect in the liquid refrigerant from the compressor, to drain through these openings below the plate due to its high specific gravity relative to the ammonia. The bottom of the casing lll marginal portions of the screen are preferably inclined downwardly so as to elevate its central portion above the plate 51 to accommodate the pipe 42 which preferably extends upwardly beyond the latter and thus prevents any oil that may accumulate below the plate from flowing into the pipe 42.

55 indicates a hood for' enclosing the float mechanism and adapted to protect the float 24a from any sudden fall or rise ofy the level of the liquid refrigerant due to starting or stopping of the pump mechanism or elevating means 12. The hood 55 comprises a sheet metal cylinder disposed horizontally axially of the member 20v and having an outer end wall 55a. lIhe inner end of the cylinder preferably telescopes on to a reduced portion of the member 20, being secured thereon by friction or otherwise if desired. As shown, the hood 55 is semi-submerged in the liquid refrigerant when the latter is at its normal level, its lower portion being formed with a plurality of openings to admit the refrigerant and at a point in the upper portion of the hood (for example, its end wall) it is formed with a Vent 56.

In. the form of construction shown in Figs. 5 and 6, the means for elevating and distributing the liquid ammonia are of a different construction, as follows: 57 indicates a plurality of flexible members, such as chains uniformly spaced longitudinally of the casing 11 between its end l walls 11b, llc. These chains at their upper ends engage sprockets 58, by which they are driven and depend downwardly therefrom to either side of the cylinder 2a, preferably sliding on the latter and their lower portions are suspended or submerged in the liquid ammonia, below its level. Accordingly, when the chains are driven, the arnmonia adheres to the chains and lodges in the spaces between its links and bars, and it is carried upwardly therewith and distributed on the walls of the cylinder 2a. The chains may be driven at a desired speed to convey sufcient arnmonia to the upper portion of the cylinder to insure the necessary heat transfer as the surplus ammonia gravitates to the lower portion of the casing. When desired, the chains may be provided with buckets or flights. The sprockets 58 are fixed to a shaft 59 which is mounted at one end in a bearing provided on one end wall of the casing 11 (for example, the front end wall 11b) The other end of the shaft is similarly mounted in the other end wall and extends therethrough for connection with the shaft of an electric motor 60 suitably mounted' on the support 1. ln this arrangement, the inlet 3 extends upwardly to one side of the support for the motor 60.

6l indicates a trough provided on the upper portion of the cylinder 2a and extending longitudinally thereof between the runs of the chains. The trough serves to collect ammonia elevated by the chains and by means of openings formed..

in the trough walls the ammonia is distributed over the walls of the cylinder 2a.

Operation: in freezing a batch of the mix" the driving means 8 are first started to set the agitating mechanism 6 in operation. Next, a measured quantity of the mix" is introduced into the cylinder 2a through the inlet 2. Next, the switch (not shown) for the circuit for the motor 50 is closed. Upon starting of the motor 50, the pumping and distributing means are set in operation, the effect of which is to distribute the ammonia onto the walls of the cylinder. The ammonia flows over the cylinder wallsv as it gravitates to the lower portion of the evaporator enclosing cas- Leconte ing 11, from which portion it is again pumped and distributed to the cylinder 2d.. As the ammonia ows over the cylinder walls, rapid absorption of heat units from the mix results. This absorbed heat is carried away in the form of gas which rises to the upper portion of the evaporator enclosing casing through the spaces between the cylinder and casing and passes out through the suction pipe 13. The supply of ammonia from the distributor is sufficient to maintain a film or sheet of the liquid on the evaporator walls so long as the pump 50 is in operation, so that ample space is provided to permit of the separa'- tion and upward ow of the gas. When the mix is frozen to the desired temperature, the motor 50 is stopped. As this operation instantly cuts off the supply of ammonia to the distributing device and that portion of the ammonia in the distributor and flowing over the evaporator walls immediately gravitates to the lower portion below the evaporator 2, heat transfer is substantially immediately arrested. By 4continuing the operation of the agitating mechanism, the mix is whipped to secure the proper yield or over-run, following which it is discharged. When a new batch of mix is introduced into the cylinder 2a,

the motor 50 is again started, which substantially instantly supplies the ammonia to the walls of the cylinder 2a. l

From the foregoing description it will be seen that the liquid ammonia is substantially instantly applied to substantially the entire exterior surface oi" the cylinder 2a. when the pump 37 is started, and when the pump 38 is stopped, the entire application of the ammonia thereto substantially instantly ceases. This permits positive control of the refrigeration and tends to speed the operations of freezing and whipping successive batches of the mix. ammonia is 'discharged above the cylinder 2a and flows downwardly thereover, it continuously washes the walls of the latter, so that any and all gas that may form in pockets betweenthese walls and the liquid flowing downwardly is dislodged from these walls by thel owing liquid and separated from the latter due to its movement, the effect of which is to insure rapid and uniform refrigeration or heat transfer over the entire cylinder. Since the Scrapers 7 have a revolving speed of approximately 175 revolutions per minute, it will be seen that a very thin film of material is allowed to adhere to the interior of the inner surface of the cylinder 2a between adjacent Scrapers as they traverse the cylinder wall before the next, rearward scraper engages therewith to remove it. Accordingly, the uniform application of the liquid ammonia to the exterior surface of the cylinder in conjunctionl with the operation of the Scrapers is advantageous to insure a uniform, smooth frozen consistency of the mix `wherein the ice crystals are finely and uniformly divided.

My construction is advantageous for the reason that discharge of the liquid ammonia from the space l0 is not dependent upon the generation of gas therein' to expel the liquid ammonia or by operation of one or more valves, but it permits the liquid ammonia to gravitate or drain at all times to a point below the evaporator 2 so that danger of explosions, due to injection of hot water f or steam into the container, is entirely eliminated.

In other words, the liquid ammonia is applied to the evaporator mechanically and gravitates thereover, as contra-distinguished from a thermal or flooded system, for which reason the construction is relatively simple, and the heat transfer is effectively and positively controlled to insure rapid as Well as uniform cooling or freezing. In such construction and method of operation, it will be noted that no valves are required to be operated to effect complete freezing of each batch or the freezing of successive batches; also, since the liquid ammonia always flows over the evaporator in one direction and does not surge into and out of its enclosing casing, its supply and cutoff are positively controlled and time is saved in carrying out the successive steps in freezing each batch, as Well as applying the liquid ammonia to each neW batch to be frozen.

In my construction the evaporator enclosing casing, Which serves as the accumulator for the supply of the volatile liquid refrigerant (and the evaporator which contains the material from which heat is to be extracted, constitute a unitary structure so arranged that the liquid refrigerant supply and the application thereof to the Walls of the evaporator is Within the casing separation of the gases from the liquid refrigerant is readily and automatically effected and no transfer of the refrigerant into and out of the casing is required. At the same time, during Whipping of the mix or when the apparatus is not in use, the evaporator walls are devoid cf heat transfer effect and the refrigerant supply is effectively insulated from external heat so that no Waste of the refrigerant results from boiling thereof or due to frosting of exposed parts.

It will also be noted that due to the circulation of the liquid refrigerant in an open space while in contact with the Walls of the cylinder 2a, that gas pockets or bubbles generated by the absorption of heat are carried away from such Walls as fast as such bubbles form and due to the .fact that there is an unfilled flow space around these Walls, the gas bubbles become automatically separated from the liquid and flow upwardly. .ls this flow space is enlarged, preferably progressively toward the top portion of the casing, the gas is drawn therefrom in a dry condition. rIhis Washing of the evaporator walls of the gas bubbles and separation thereof from the liquid prevent these bubbles from insulating the evaporator Walls, and danger of the bubbles exploding and ejecting both the liquid and gas into the suction pipe is avoided. This process of applying the liquid refrigerant and carrying off the gas bubbles serves to increase the transfer of heat so that the freezing step is effected expeditiously.

To those skilled in the art to Which my invention relates, many changes in construction and Widely differing embodiments and applications of the invention Will suggest themselves Without departing from the spirit and scope thereof. My disclosures and the description herein are purely illustrative and not intended to be in any sense limiting.

What I claim is:

l. In a heat transfer and gas separatingv mechanism, the combination of a casing having insulated walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; an automatically controlled supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; and means for circulating the refrigerant within the casing into contact with the Walls of said evaporator.

2. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for holding materials from which heat is to be extracted Within said casing and in spaced relation to its side Walls and above the normal level of the refrigerant therein and supported in the end Walls of said casing; and means for circulating the refrigerant Within said casing into contact with' the Walls of said evaporator.

3. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for holding materials from which heat is to be extracted Within said casing and in spaced relation to its side Walls and above the normal level of the re frigerant therein and supported in the ends Walls of said casing; the heads for said evaporator being exposed outside the end walls of said casing, one of said heads being provided with a material inlet and one of said heads being provided with a valved discharge outlet; and means for circulating the refrigerant within said casing into contact with the Walls of said evaporator.

4. In a heat transfer and gas separating mechanism, the combination of casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for con-l taining materials from which heat is to be extracted supported Within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; and means for circulating the refrigerant Within said casing substantially in the form of a nlm into contact with the Walls of said evaporator.

5. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; and means for elevating the refrigerant Within said casing and distributing it onto the Walls of said evaporator substantially in the form of a film.

6. In a heat transfer and gas separating mechanism, the combination of a casing having insulated walls and forming a combined Aaccumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; and means for elevating the refrigerant within said casing and distributing it onto the walls of said evaporator and permitting it to gravitate thereover.

7. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; said casing being shaped to enlarge the space above said evaporator; and means for circulating the refrigerant substantially in a film in contact with the walls of said evaporator and permitting it to gravitate thereover.

8. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its Walls and above the normal level of the refrigerant therein; said casing being shaped to enlarge the space above said evaporator; and means for elevating the refrigerant above said evaporator and permitting it to gravitate over its Walls.

9. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its walls above the normal level of the refrigerant therein; means for circulating the refrigerant into contact With the Walls of said evaporator; and means in said casing for separating oil from the refrigerant.

10. In a heat transfer and gas separating mechanism, the combination of a casing having insulated walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported within said casing and in spaced relation to its Walls above the normal level of the refrigerant therein; means for circulating the refrigerant into contact with the Walls of said evaporator; and means below the level of the refrigerant Within said casing and located in said casing for separating oil from the refrigerant.

l1. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its walls and above the normal level of the refrigerant therein; means for circulating the refrigerant within said casing into contact with the Walls of said evaporator; and means below the level of the refrigerant in said casing for separating oil from the refrigerant, said separating means comprising a plate disposed in spaced relation to the bottom of said casing and engaging the sides thereof, one edge of said plate being formed with notches.

12. In a heat transfer and gas separating mechanism, the combination with a support provided with a case having insulated walls; of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; the lower portion of said insulated casing being enclosed in said case; a suction connection leading from the upper portion of said casing; valved supplyl means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its walls and above the normal level of the refrigerant therein; and means for circulating the refrigerant within said casing in contact with the Walls of said evaporator.

13. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls, said casing being elongated vertically and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials, from which heat is to be extracted, supported Within the upper portion of said casing above the normal level of the refrigerant therein; and means for circulating the refrigerant Within said casing in contact with the walls of said evaporator; the upper portion of said casing being spaced from the walls of said evaporator to permit flow of the liquid refrigerant through the space in contact with said walls and separation from the liquid of gases due to absorption of heat.

14. In a heat transfer and gas separating mechanism, the combination of a casing having insulated walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported Within said casing and in spaced relation to its walls and above the normal level of the refrigerant therein; a distributing device in said casing and above said evaporator for discharging the refrigerant onto the Walls of said evaporator; and means for conveying the refrigerant in the accumulator to said device.

l5. In a heat transfer and gas separating mechanism, the combination of a casing having insulated Walls and forming a combined accumulator for a volatile liquid refrigerant and a gas separator; a suction connection leading from the upper portion of said casing; valved supply means for the refrigerant; an evaporator for containing materials from which heat is to be extracted supported within said casing and in spaced relation to accumulator for a volatile liquid refrigerant, a M5 gas separator and an enclosure for said evaporator; said evaporator being disposed above the normal level of the refrigerant in said casing and in spaced relation to the Walls thereof for permitting separation of the gas from the liquid refrig- 15() erant during circulation thereof; a suction connection leading` from the upper portion of said casing; valved supply means for the refrigerant;

and means for circulating the refrigerant within the casing into contact with the walls of said evaporator.

17. In a heat transfer and gas separating mechanism, the combination of an evaporator for containing materials from which heat is to be extracted; an insulated casing forming a combined accumulator for a volatile liquid refrigerant, a gas separator and an enclosure for said evapora- MICHAEL H. ACKERMAN. 

